As we come on the air, 10,000 law enforcement officers are trying to find a killer in los angeles, california. A sweeping manhunt, triggered by this man. A former policeman, accused of a shooting spree, targeting fellow cops and their families. And these images say it all. Police officers on the hunt for someone who knows their coldcodes, their moves. On highways, a request that commuters study license plates and call 911. And tonight, a city is on the edge. Abc's david wright is there. David? Reporter: Good evening, diane. Tonight, police officers across this whole region feel they are under attack. Police headquarters here on lockdown. Every entrance, every exit, heavily guarded. The entire police force in america's second largest city, essentially held hostage to one man who is allegedly bent on revenge. Tonight, by air, land and sea, an all-out manhunt. The suspect, one of thei 33-year-old christopher dorner. A former lapd officer, now an alleged cop killer. Police say he isn't just targeting cops, but their families, too. This has gone far enough. You know, nobody else needs to die. Reporter: The killing spree started sunday in orange county, with the baffling double murder of a popular college basketball coach and her fiance. Monica quan and keith laurence, shot in cold blood as they sat in their car. Only last night did authorities put two and two together. Quan is the daughter of retired lapd captain randy quan, who was instrumental in getting christopher dorner fired. In a rambling manifesto posted online, dorner blames quan and other lapd officers of a smear campaign, after dorner reported witnessing a fellow officer commit police brutality. The manifesto vows vengeance. "I will bring unconventional and asymmetrical warfare to those in lapd uniform whether on or off duty." Early this morning, it appeared that was no idle threat. 1:25 a.M., An hour east of l.A. Police officers acting on a tip exchanged gunfire with a man believed to be dorner. An officer, grazed by the bullet. Unable to pursue. 1:45, riverside. Two more officers on a protective detail ambushed. One killed, the other seriously injured. By sunrise, jittery police had opened fire on this blue truck in torrance. A nissan titan, just like the suspect's. But the people inside were innocent bystanders. Police are now closing ranks, protecting themselves. Today, motorcycle cops were put in patrol cars. More than 40 protective details deployed to guard people named in the manifesto. Police families are taking no chances. Keeping kids home from school. The los angeles police department and law enforcement agencies are implementing all measures possible to ensure the safety of our lapd personnel, their families and the los angeles community. Reporter: Meanwhile, there's a region-wide manhunt. Late today, police spotted this truck, burning in the mountains northeast of l.A. It has now been confirmed that that was, indeed, the suspect's vehicle. But it has also been confirmed that the suspect was not idea. He appears to have fled, and, so, diane, the manhunt continues. All right, david, thank you.

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